feat: Add alpha feature verification to feature gates

Implement a new function, verifyAlphaFeatures, to ensure that alpha features cannot be enabled by default. Update the verifyOrUpdateFeatureList function to call this new verification. Add corresponding unit tests to validate the behavior of alpha feature handling.

test/compatibility_lifecycle/cmd/feature_gates.go

@@ -134,6 +134,10 @@ func verifyOrUpdateFeatureList(rootPath, featureListFile string, currentVersion
 	}
 	featureList = append(featureList, features...)
 
+	if err := verifyAlphaFeatures(featureList); err != nil {
+		return err
+	}
+
 	sort.Slice(featureList, func(i, j int) bool {
 		return strings.ToLower(featureList[i].Name) < strings.ToLower(featureList[j].Name)
 	})
@@ -175,7 +179,7 @@ func verifyOrUpdateFeatureList(rootPath, featureListFile string, currentVersion
 }
 
 func dedupeFeatureList(featureList []featureInfo) ([]featureInfo, error) {
-	if featureList == nil || len(featureList) < 1 {
+	if len(featureList) < 1 {
 		return featureList, nil
 	}
 	last := featureList[0]
@@ -262,6 +266,17 @@ func verifyFeatureRemoval(featureList []featureInfo, baseFeatureList []featureIn
 	return nil
 }
 
+func verifyAlphaFeatures(featureList []featureInfo) error {
+	for _, f := range featureList {
+		for _, spec := range f.VersionedSpecs {
+			if spec.PreRelease == "Alpha" && spec.Default {
+				return fmt.Errorf("alpha feature %s cannot be enabled by default", f.Name)
+			}
+		}
+	}
+	return nil
+}
+
 func searchPathForFeatures(path string) ([]featureInfo, error) {
 	allFeatures := []featureInfo{}
 	// Create a FileSet to work with

test/compatibility_lifecycle/cmd/feature_gates_test.go

@@ -894,3 +894,53 @@ func TestVerifyFeatureRemoval(t *testing.T) {
 		})
 	}
 }
+
+func TestVerifyAlphaFeatures(t *testing.T) {
+	tests := []struct {
+		name           string
+		featureList    []featureInfo
+		expectErr      bool
+		expectedErrMsg string
+	}{
+		{
+			name: "no alpha features",
+			featureList: []featureInfo{
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+				{Name: "FeatureC", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "GA", LockToDefault: true}}},
+			},
+		},
+		{
+			name: "alpha feature disabled",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha", Default: false}}},
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+		},
+		{
+			name: "alpha feature enabled",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha", Default: true}}},
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+			expectErr:      true,
+			expectedErrMsg: "alpha feature FeatureA cannot be enabled by default",
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			err := verifyAlphaFeatures(tc.featureList)
+			if tc.expectErr {
+				if err == nil {
+					t.Fatalf("expected error, got nil")
+				}
+				if !strings.Contains(err.Error(), tc.expectedErrMsg) {
+					t.Fatalf("expected error message to contain %q, got %q", tc.expectedErrMsg, err.Error())
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+		})
+	}
+}